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Vegetarian mushroom and spinach lasagna in baking dish with golden melted cheese on top

Vegetarian Mushroom and Spinach Lasagna

A hearty vegetarian lasagna featuring layers of tender pasta, savory mushrooms, fresh spinach, and three types of cheese in rich marinara sauce.
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Prep Time 25 minutes
Cook Time 45 minutes
Resting Time 10 minutes
Total Time 1 hour 20 minutes
Servings: 6 portions
Course: Dinner, Main Course
Cuisine: American, Italian
Calories: 350
Ingredients Equipment Method Notes

Ingredients
  

  • 9 lasagna noodles
  • 1 pound cremini or button mushrooms sliced
  • 6 cups fresh spinach or 10 oz frozen spinach, thawed and squeezed dry
  • 1 medium onion diced
  • 3 cloves garlic minced
  • 2 cups whole milk ricotta cheese drained if watery
  • 1⅔ cups shredded mozzarella cheese divided: ⅔ cup for layering, 1 cup for topping
  • ½ cup grated Parmesan cheese
  • 3 cups marinara sauce store-bought or homemade
  • 2 tablespoons olive oil
  • 1 teaspoon dried Italian seasoning
  • Salt and black pepper to taste

Equipment

  • 9x13-inch baking dish
  • Large skillet
  • Large pot for boiling pasta
  • Aluminum foil
  • Fine-mesh strainer (optional, for draining ricotta)

Method
 

  1. Preheat your oven to 375°F. Cook the lasagna noodles according to package directions until al dente (usually 8-10 minutes), then drain and lay them flat on a baking sheet drizzled with olive oil to prevent sticking.
  2. While noodles cook, heat 2 tablespoons of olive oil in a large skillet over medium-high heat. Add the diced onion and cook for 3-4 minutes until softened and translucent. Add the minced garlic and cook for another 30 seconds until fragrant but not browned.
  3. Add the sliced mushrooms to the skillet and cook for 8-10 minutes, stirring occasionally, until they've released their moisture and the liquid has evaporated. The mushrooms should be golden brown and the pan should look fairly dry. Add the spinach in batches if using fresh, stirring until wilted (about 3-4 minutes total). If there's excess liquid in the pan, drain it off to prevent a watery lasagna. Season with Italian seasoning, salt, and pepper. Remove from heat and set aside.
  4. In a 9x13-inch baking dish, spread 1 cup of marinara sauce evenly across the bottom. Layer 3 lasagna noodles over the sauce, slightly overlapping if needed depending on your noodle brand.
  5. Spread half of the ricotta cheese over the noodles using the back of a spoon, then top with half of the mushroom-spinach mixture, spreading it evenly. Sprinkle with 1/3 cup mozzarella and 2 tablespoons Parmesan. Pour 1 cup of marinara sauce over the cheese layer, spreading gently to cover.
  6. Repeat the layering process: 3 noodles, remaining ricotta, remaining mushroom-spinach mixture, 1/3 cup mozzarella, 2 tablespoons Parmesan, and 1 cup marinara sauce.
  7. Top with the final 3 lasagna noodles, spread the remaining marinara sauce over them completely, and finish with the remaining 1 cup mozzarella and remaining Parmesan cheese.
  8. Cover the baking dish tightly with aluminum foil (spray the underside with cooking spray to prevent cheese from sticking) and bake for 25 minutes. Remove the foil and bake for an additional 15-18 minutes until the cheese is golden brown and bubbly around the edges. Let the lasagna rest for 10 minutes before slicing.

Notes

This lasagna can be assembled up to 24 hours in advance and refrigerated until ready to bake. Add 5-10 minutes to covered baking time if baking from cold. Leftovers keep well in the refrigerator for up to 4 days or can be frozen for up to 3 months. To freeze unbaked, wrap tightly in plastic wrap then aluminum foil and bake from frozen, adding 15-20 extra minutes to the covered baking time.